Every customer has specific equipment design requirements, and those requirements significantly affect the process control demands. Therefore, our control systems are highly flexible and adjustable to meet customers’ specific needs. Although designs vary from system to system, the following facts are standard for our control systems: highest accuracy, minimal delays, friendly, easy-to-use user interface, and safety as the priority.
The primary function of all Ovens and Furnaces is temperature precision. That is why we use several thermocouples at different places in the Ovens and Furnaces to detect the temperature inside the heating equipment, to ensure uniformity across all sections. The accomplishment of uniform temperature distribution in the Oven or Furnace is indeed an art that combines science and engineering. We successfully design systems for the most stringent operating parameters, where all sections of the unit are within 5 °F range.
As part of the engineering and system design process, Epcon’s team determines the appropriate number of re-circulating and exhaust fans with dampers, and vacuum ports, along with their size and positioning based on the processing unit’s required capacity and operating parameters, with details provided by the customer. The RPM of each fan and dampers’ percentage openings are automatically adjusted to meet the set criteria, enable constant airflow, and maintain the processing unit’s set pressure. The complex programmed control algorithm secures the optimized process at all times with the highest feasible thermal efficiency.
In addition, Epcon installs flow sensors throughout the air and gas process stream within the industrial process. The highest accuracy actuator automatically regulates air’s and gas’ flow based on user demand. Our custom programmed algorithm enables users to enter their target oxygen percentage directly, and the actuator will adjust the flows accordingly. Another manipulative variable that users may adapt in real-time is natural gas pressure since our PLC panel enables the compressors’ control based on the pressure transmitter response.
Most industrial boiler manufacturers utilize Siegert’s Formula as the combustion efficiency model to express the natural gas combustion process’s quality and take that value as the relevant one for the whole heating process. The issue with this model is that it is not 100% accurate as it only involves the temperature of air combustion and stack temperature besides the natural gas quality coefficient. The boundary-value of thermal efficiency that every Oven and Furnace must reach is 90%. The thermal efficiency calculation that we utilize includes the highly accurate temperature-dependent specific heat capacities of the materials that are heated. Therefore, all heat losses, even the minor ones such as ones by radiation and the loss in the insulation layer, are accounted for in the model we use. Before transportation of the equipment to customers, our team performs the final testing to ensure your equipment operations are as efficient as possible and operates exactly as designed.
Epcon Industrial Systems provides custom-designed Allen Bradley ContolLogix Programmable Logic Controller (PLC) with Panel-view plus that includes the following:
- HMI Rockwell Factory Talk View Site Edition Station Unlimited Display
- 120 V digital output modules for controlling all manipulative variables
- 120 V digital input modules for signals monitoring
- Analog input modules
- Thermocouple modules
- 10% of spare I/O points for eventual further additions of the control system
- Software with graphic display
For cases of abrupt loss of power supply, we provide the uninterruptible back up power source for the 120V control circuit to operate PLC and operator interface for 60 minutes. The UPS represents a real online model with field-replaceable maintenance-free batteries.
The PLC is connected to an HMI Rockwell Factory Talk View Site Edition Station Unlimited Display. Epcon team installs and verifies the HMI software functionality on the customer-provided computer during the heating unit installation. A user-friendly interface allows the operator to define 25 cycle descriptions and several key operating steps within the process.
The issue with entering operating parameters manually between sessions is that it leaves space for human error. Still, more importantly, it causes delays in process’ stages. For example, if the operator needs 10 seconds to enter the new parameters between process stages and the process possesses 12 different stages, the result is 2 minutes, where the system does not run according to design, which is unacceptable in modern industrial production.
Usage of the digital input and output model enables minimal delays in transferring information in both ways, to and from the software. Another great advantage of the digital modules is that the process data is permanently stored. Data acquisition software is provided for customer-defined operating parameters. In that way, besides real-time monitoring, users can analyze the process at any point in the past time.
Another key function of the systems controls is safety and hazard prevention. We ensure all our equipment meets strict OSHA operating standards by programming a system shut down immediately if one of the following requirements is fulfilled:
- Oven or Furnaces door open with inner temperature over 150°F (Door switch)
- Heating units over-temperature state
- Heating/Recirculation chamber over-temperature condition
- Loss of airflow of each fan (airflow switch)
- PLC failure
Additional requirements are considered according to process specifications, however these basic safety measures are built into every Process Heating unit that Epcon delivers.
When designing a control system, it is a priority to include features that allow operators to monitor system accuracy, and make real-time adjustments, while guaranteeing basic safety and hazard prevention.
Visit us at https://www.epconlp.com for more details.